Cataracts: Definition, Types, Causes, Symptoms, Treatment, and Prevention

Published on July 7th, 2023

Updated on May 21st, 2024

Cataracts are a type of age-related eye disease that forms in the eye lens as a result of clumping protein that has broken down, leading to a decline in clear vision. The causes of cataracts are most commonly due to age but other causes include trauma to the eye, diabetes and certain medications. The cataract symptoms include cloudy or blurred vision, double vision in one eye and poor night vision. Other signs of cataracts include increased sensitivity to light and frequently changing glasses prescriptions. The three main types of cataracts include nuclear, cortical and posterior subcapsular cataracts. The treatment for a cataract is surgery which involves replacing the affected lens with an artificial one. Wearing sunglasses can be a form of prevention as they may help to delay the onset of early cataracts. Keep reading to find out more about the types of cataracts, the symptoms and how they may be treated.

What is a Cataract?

A cataract is a clumping of protein in the eye’s lens which causes the lens to become cloudy instead of clear, which is called opacification. According to the Mayo Clinic, a cataract typically forms due to age as the lens naturally breaks down, but can also be due to trauma to the eye such as an injury. An early-stage cataract typically has no symptoms, but as the condition progresses, symptoms may include sensitivity to lights, poor night vision and blurred and cloudy vision. To summarise, the answer to the question of what are cataracts; cataracts are an age-related common eye problem that causes the lens to look cloudy and can affect a person’s vision.

What Does a Cataract Do to the Eye?

A cataract causes the lens of the eye to become cloudy, affecting a person's vision. According to the Mayo Clinic, advanced cataracts can become visible and appears as a cloudy or white film over the eyeball. A cataract can cause several symptoms that affect the eyes and vision, these include blurred or cloudy vision, sensitivity to light, difficulty seeing at night, seeing halos around lights and double vision. According to Vision Australia, cataracts are one of the leading causes of vision impairment.

What Part of the Eye Do Cataracts Affect?

The part of the eye that cataracts affect is the lens which can cause it to appear cloudy or white. This is due to the proteins in the eye breaking down and clumping together which can affect a person’s vision. The lens is a transparent structure and is the part of the eye that helps the eye focus light onto the retina. Damage to the lens can cause a cataract to form.

What are the Different Types of Cataracts?

There are many different types of cataracts that can affect different parts of the eye and develop due to different causes. The different types of cataracts include cortical cataracts, congenital cataracts, nuclear cataracts, secondary cataracts, traumatic cataracts and posterior subcapsular cataracts. These types of cataracts and their definitions are listed below.

Cortical cataracts: Cortical cataracts are a common type of cataract that is characterised by opacification of the lens fibres surrounding the centre of the lens, known as the nucleus.
Congenital cataracts: Congenital cataracts are defined as having some presence of cataracts at birth. A congenital cataract is a birth defect that affects the baby’s ability to see.
Nuclear cataracts: Nuclear cataracts affect the centre of the lens, which is called the nucleus. A nuclear cataract is one of the most common cataracts and is one of the three main types of age-related cataracts.
Secondary cataracts: A secondary cataract, also known as posterior capsule opacification, occurs due to scar tissue that may develop after cataract surgery.
Traumatic cataracts: Traumatic cataracts describe cataracts caused by eye injuries where the lens is damaged. Cataracts due to an eye injury may develop soon after or it can occur years later.
Posterior subcapsular cataracts: A posterior subcapsular cataract is a type of age-related cataract that is located in the posterior cortical layer which is under the lens capsule.

1. Cortical Cataracts

Cortical cataracts are a common type of age-related cataracts that is characterised by opacification of the lens fibres surrounding the centre of the lens, known as the nucleus. According to the American Academy of Ophthalmology, this type of cataract impacts a person’s vision depending on how close the opacities on the lens are to the centre of the eye, known as the visual axis. The progression of cortical cataracts can vary from a few months to over a few years. The symptoms of cortical cataracts include seeing glare around lights, specifically when driving, a decreased ability to see near and far distances and diminished vision contrast sensitivity.

2. Congenital Cataracts

Congenital cataracts occur when a baby is born with a degree of opacity in their lens. A congenital cataract is a birth defect that affects the baby’s ability to see as the light coming into the eye is affected by the cloudy part of the lens. It is important for congenital cataracts to be treated early as, if left untreated, it can lead to vision problems and eventual blindness. There is also an increased risk of developing this type of cataracts if there is a family history of this eye condition according to Medical News Today.

3. Nuclear Cataracts

A nuclear cataract is one of the most common cataracts and is one of the three main types of age-related cataracts, the other two being cortical and posterior subcapsular cataracts. According to the Mayo Clinic, nuclear cataracts affect the centre of a patient’s lens which is known as the nucleus and as it progresses, it turns the lens yellow which clouds their vision leading to issues with eyesight. Nuclear cataracts can actually increase a person's near vision due to the core of the lens hardening, which may cause people who previously had reading glasses to not need them.

4. Secondary Cataracts

A secondary cataract, also known as posterior capsule opacification, occurs due to scar tissue that may develop on a patient’s lens after cataract surgery. This complication of cataract surgery is common according to the National Eye Institute and can be treated easily. Treatment for secondary cataracts is a painless procedure that involves a laser making an opening in the cloudy part of the patient’s lens. According to the American Academy of Ophthalmology, experiencing blurry vision or a decline in clear and sharp vision after cataract surgery are signs of secondary cataracts and should be assessed by an eye doctor or optometrist.

5. Traumatic Cataracts

Traumatic cataracts describe cataracts caused by eye injuries where the lens is damaged. Cataracts due to an eye injury may develop soon after the injury or it can occur years later. According to the American Academy of Ophthalmology, traumatic cataracts are not only caused by penetrating or blunt trauma but they can also be caused by radiation, electrocution and chemical burns. The main symptom of a traumatic cataract is the clouding of the lens at the site of the injury which may spread to the whole lens. According to an article published in Science Direct, this type of cataract can be diagnosed through an examination of the patient's lens, typically using a slit lamp.

6. Posterior Subcapsular Cataracts

A posterior subcapsular cataract is a type of age-related cataract that is located in the posterior cortical layer which is under the lens capsule, affecting the back of the lens. According to the American Academy of Ophthalmology, posterior subcapsular cataracts are often more common in younger people compared to other types such as nuclear and cortical cataracts. The symptoms of posterior subcapsular cataracts include seeing glare, struggling to see in bright light and diminished near and far vision. According to the Mayo Clinic, this type of cataract typically progresses quicker than others.

What Causes Cataracts to Form?

The most common cause of cataracts is age as the eye naturally changes when a person gets older, which can cause a cataract to form within the eye. According to the National Eye Institute, once a person reaches around the age of 40, the proteins in the eye’s lens begin to break down and subsequently clump together, making the eye become cloudy; this is known as a cataract. Other causes of cataracts include being born with cataracts, known as congenital cataracts. Trauma to the eye may cause a cataract to form due to damage sustained by the lens. People with diabetes have an increased risk of developing cataracts. Secondary cataracts are a type of cataract that form after cataract surgery due to the development of scar tissue as a result of the surgery that can cause a person’s vision to become cloudy again. What causes cataracts can be due to multiple factors but the most common type is the natural ageing process.

What are the Risk Factors of Cataracts?

The risk of developing cataracts increases with age, however, there are other risk factors that may contribute to cataracts forming on a person’s eye. The risk factors of cataracts according to the National Eye Institute are smoking, diabetes, excessive alcohol consumption, having a family history of cataracts, taking steroid medication, spending long periods in the sun, sustaining an eye injury or having had eye surgery. The potential risk factors for cataracts and their definitions are listed below.

Smoking: Smoking can increase a person's risk of cataracts as it can damage the proteins in the eye. According to the American Food and Drug Administration, smokers are two to three times more likely to develop cataracts.
Diabetes: People with diabetes are at a higher risk of developing cataracts as high blood sugar can lead to changes in the lens which can speed up the formation of a cataract.
Alcohol: Heavy consumption of alcohol is a risk factor for cataracts as it may cause optic nerve damage and nutritional deficiencies, speeding up the process of age-related cataracts.
Family history of cataracts: If a person has a family history of cataracts, they are at higher risk of developing congenital cataracts. This type of cataract causes the eye to be cloudy at birth instead of it developing over time.
Steroid medications: Steroid medications can be used to treat certain health conditions or problems such as allergies or arthritis. Steroids may increase a person’s risk of cataracts as they can cause a cloudy area to form in the lens.
The sun: Spending prolonged periods in the sun without proper UV protection in the form of sunglasses may increase the risk of a cataract forming on the eye.
Eye injuries: Eye injuries can lead to the development of a cataract on the lens due to the damage it sustains.
Eye surgery: Eye surgery and especially cataract surgery can cause a cataract to form due to the development of scar tissue. Scar tissue as a result of eye surgery can cause a person’s vision to become cloudy again. This is known as secondary cataracts.

Is Taking Certain Medications a Risk for Developing Cataracts?

Yes, certain medications can increase a person’s risk of developing cataracts. According to an article published in the National Library of Medicine, steroid medication is among those medications with steroid-induced cataracts often caused by glucocorticoid steroids. Also, according to Reuters, certain pain medications, diabetes medication and some antibiotics have been linked to increasing a person’s risk of cataracts.

Are Cataracts Hereditary?

Yes, cataracts can be hereditary which is known as congenital cataracts as it is a genetic disease. This type of cataract causes the eye to be cloudy at birth instead of it developing over time. According to Medical News Today, people who have a family history of cataracts, are more likely to develop this condition.

What are the Symptoms of Cataracts?

People may not experience symptoms when they first develop cataracts but as the condition progresses, there are multiple symptoms that may occur. The possible cataract symptoms include blurred or cloudy vision, sensitivity to bright lights, difficulty seeing at night, perceiving halos around light sources, colours appearing dull or yellowish, double vision and frequent adjusting glasses or contact lenses. The possible symptoms of cataracts and their definitions are listed below.

Blurred or cloudy vision: A cataract on the lens can affect a person’s eyesight, causing blurred or cloudy vision. Blurred vision is also a common symptom of refractive errors while cloudy vision is most often caused by cataracts.
Sensitivity to bright lights: Sensitivity to bright lights such as headlights and lamps is a common symptom of a cataract. This symptom is also known as photophobia and can cause people to squint.
Difficulty seeing at night: Poor night vision is a symptom of cataracts, meaning a person struggles to see at night or in poor lighting. This can affect a person when driving or in the cinema.
Perceiving halos around light sources: A person with a cataract may perceive halos and glare around light sources. Halos are most commonly noticed in a low-light room or at night.
Colours appear dull or yellowish: Advanced cataracts may affect a person’s colour vision as the vision is passing through the cataract, which may dull the colours or make things appear yellowish.
Double vision: Double vision may occur in one eye due to the cataract formation on the lens disrupting vision. Double vision occurs when light does not hit both of the retinas at the same point, causing the eyes to see two distinct or overlapping images.
Frequently adjusting glasses or contact lenses: Frequently adjusting glasses or contact lenses is a symptom of cataracts as the condition can change the eye’s focusing power, making it difficult to see clearly.

1. Blurred or Cloudy Vision

Blurred or cloudy vision is a symptom of cataracts as the condition interferes with the lens’ ability to focus and receive light. While typically cataract symptoms can be corrected through prescription glasses, this is mostly not the case for cataracts except when in the early stages. In later stages, the cataract that is affecting a person’s vision will only be cured through surgery. A person with cataracts may experience blurred or cloudy vision due to the disruptions to their lens.

2. Sensitivity to Bright Lights

Sensitivity to bright lights such as headlights and lamps is a common symptom of cataracts. Light sensitivity, also known as photophobia, refers to eye pain or discomfort when the eyes are exposed to light, which often causes people to squint. If you have heightened sensitivity to light, it is important to seek medical care. Sensitivity to bright lights in the context of cataracts occurs due to the eye’s lens not being clear, causing light that enters the eye to scatter. This also causes other vision problems such as blurred and cloudy vision.

3. Difficulty Seeing at Night

People with a cataract may have difficulty seeing at night or in dimly lit areas. This difficulty is caused by the eyes taking a long time to adjust when transitioning from light to dark. Having poor night vision can affect a person when driving or in the cinema. Driving at night with cataracts vision is also difficult due to the glare seen around headlights and other sources of light as well as a sensitivity to light. If you struggle with seeing at night or in low-light areas, it is advisable to seek an assessment from a healthcare or eye care professional.

4. Perceiving Halos Around Light Sources

A person with a cataract may perceive halos and glare around light sources. Halos are most commonly noticed in a low-light room or at night. A halo around lights is described as colourful and bright circles and can significantly impact a person’s vision, especially when driving at night. Perceiving halos around lights is a common symptom of cataracts and is caused by a clumping of proteins within the lens, which causes light to scatter as it enters the eye.

5. Colours Appear Dull or Yellowish

Advanced cataracts may affect a person’s colour vision as the light passing through the cataract may dull colours or make vision appear yellowish. Some describe cataracts vision as seeing faded colours and a discolouration of certain colours. According to a study published in the National Library of Medicine, age-related cataracts have a major impact on a patient’s colour vision. The study defines colour perception as light transmittance via the optical system, including the lens, cornea and pupil. Another way colour is affected by cataracts is through a reduction in contrast in retinal images.

6. Double Vision

Double vision, also known as diplopia, may occur in one eye due to a cataract formation on the lens, disrupting vision. This type of double vision is referred to as monocular double vision, and is often referred to as “ghosting”. The cloudiness of the lens causes light to scatter and form multiple, but incomplete images. As a result, this type of double vision occurs even when one eye is shut.

7. Frequently Adjusting Glasses or Contacts Lens Prescription

A person with cataracts may frequently adjust their glasses or contact lens prescription as the cataract is interfering with their vision. A cataract can change the eye’s focusing power, which can make a person’s vision blurry and make it difficult to see objects clearly, prompting them to get a new, stronger prescription for their lenses. According to the Mayo Clinic, in the early stages of a cataract, glasses may help a person’s vision although as it progresses, a glasses prescription will not help correct vision problems; surgery is the only option.

How are Cataracts Diagnosed?

Cataracts are diagnosed by an optometrist or other eye care professional during an eye test. According to the Mayo Clinic, there are three main tests used to diagnose a cataract. These tests include a visual acuity test, a slit-lamp exam and a retinal exam. A visual acuity test will be performed to test if the patient's vision is impaired. This test involves reading letters off a chart which will determine the clarity and sharpness of a patient’s eyesight. A slit-lamp exam allows the eye care professional to look at the structures in the eye including the lens, cornea and iris. A retinal exam involves dilating the patient’s eyes so the optometrist can look at the back of the eyes to look for signs of a cataract.

How Does Knowing Which Eye is Dominant Help Cataracts?

Knowing which eye is dominant may help with cataracts as ophthalmologists can use this information when planning cataract surgery and other eye surgeries. You can determine your dominant eye by using a dominant eye test, which can be done at home. The three types of test to determine your dominant eye include the hole-in-a-card test, miles test and the point test.

What is the Most Diagnosed Cataract?

The most commonly diagnosed form of cataracts is age-related cataracts which include nuclear, cortical and posterior subcapsular cataracts. According to Medibank Australia, more than 700,000 people in Australia are affected by cataracts. Age-related cataracts occur due to the natural ageing process and a person’s risk for this type of cataracts can be increased if they smoke, drink excessively, have diabetes and have a family history of cataracts. Age-related cataracts can be diagnosed through an eye test performed by an optometrist. Tests for age-related cataracts may include a slit lamp test and a visual acuity test.

Can a Slit Lamp Exam Diagnose Cataracts?

Yes, a slit lamp exam can diagnose cataracts as it enables the optometrist to examine the inside of a patient’s eye. A slit lamp exam is used to detect cataracts, glaucoma, corneal abrasion and dry eyes and may require pupil dilation before the process starts.

Can you do a Preliminary Diagnosis for Cataracts with a Free Eye Test at Oscar Wylee?

No, you cannot do a preliminary diagnosis for cataracts with a free eye test. You cannot do a preliminary diagnosis for cataracts as it requires a slit lamp examination, which is conducted after the preliminary diagnostic tests. You cannot get a free eye test at Oscar Wylee, they are bulk billed, which means there will be no out-of-pocket payments for eligible Medicare cardholders.

How can Cataracts Cause Blindness?

According to HealthDirect, cataracts cause blindness as the proteins that clump together on the lens block the amount of light that can pass through to the retina, leading to loss of vision and without treatment, eventual blindness. There is no specific time frame for how long before cataracts cause blindness as it can be different depending on the person and type of cataracts. In some cases it can take years and in others months. It is important to have your eyes checked by an optometrist if you suspect you have cataracts or have been diagnosed with this condition as they can monitor its progression and recommend treatment.

Are Cataracts and Glaucoma Related?

No, cataracts and glaucoma are not related although they are both linked to age and can lead to eventual vision loss and blindness. Although vision loss caused by cataracts may be reversed through cataract surgery, this is not the case for glaucoma. According to the Glaucoma Associates of Texas, the eye condition glaucoma does not cause cataracts but these two conditions can occur at the same time due to the risk of these conditions increasing as you get older.

How are Cataracts Treated?

The most common treatment for cataracts is cataract surgery. Cataract surgery is a very common surgery that is performed to restore a person’s vision that has been affected by cataracts. According to Better Health Victoria, cataracts are treated by removing the cloudy lens of the eye through surgery. Once the lens is removed, it is then replaced with a plastic, artificial lens, known as an intraocular lens which stays there permanently. Eye surgery for cataracts is performed by an ophthalmologist and, according to the Mayo Clinic, the procedure typically takes an hour or under. Recovery from cataract surgery can typically take a few days and the progress will be monitored by an eye doctor with a full recovery often taking eight weeks.

What is the Benefit of Lutein in Cataracts?

The benefit of lutein in cataracts is their potential aid in prevention. Lutein may be beneficial for cataracts due to its nutrients that can assist with preventing oxidative pressure in the back of the eye. Additionally, the benefits of lutein have been reported to include positive effects on the brain which is what can contribute to ocular function. However, there is still conflicting evidence and therefore makes it difficult to conclude that lutein is beneficial for cataracts according to the National Library of Medicine.

What is the Success Rate of Cataract Surgery?

Cataract surgery has a very high success rate as it is a very common procedure used to treat cataracts. According to Vision Australia, cataract surgery is one of the most successful and common surgical procedures performed in Australia. According to Better Health Victoria, there are approximately 250,000 cataract surgeries performed in Australia every year.

How Much Does Cataract Surgery Cost?

The cost of cataract surgery can vary depending on who performs the surgery, the location, and the condition of the patient's eye. For more information about the cost of cataract surgery, speak to your primary healthcare provider.

Is Cataract Surgery Painful?

According to the Cleveland Clinic, cataract surgery is not typically painful and patients generally experience no pain after surgery, during their recovery. Pain medication may be prescribed if a patient is experiencing a gritty feeling in the eyes or discomfort. If you are experiencing significant pain after cataract surgery, seek an assessment from a healthcare professional.

Is Cataract Curable Without Surgery?

No, currently cataracts are only curable through surgery. A cataract can be removed during surgery which will restore the vision that is blocked by the protein that has clumped on the lens. According to Better Health Victoria, once a cataract is removed in surgery, it cannot redevelop. Currently, surgery is the only way to cure cataracts but, according to the American Academy of Ophthalmology, nonsurgical treatment for cataracts is an active area of research.

Can People With Uveitis Develop Cataracts?

Yes, people who have uveitis can develop cataracts, known as uveitis cataract. According to the American Academy of Ophthalmology, cataracts are among the most common complications in people who have chronic uveitis. Uveitis is an eye condition that causes inflammation in the eye due to an infection or an autoimmune disease. A uveitis cataract is often caused by prolonged and uncontrolled inflammation in the eye.

Can Prescription Glasses Help Treat Cataracts?

No, prescription glasses cannot help treat cataracts as the blurry and cloudy vision caused by this disease is due to the clumping of protein on the lens, not a refractive error. Prescription glasses are most commonly used to correct vision problems caused by refractive errors such as nearsightedness, farsightedness and astigmatism. While glasses may help in the early stages of a cataract's progression, the main treatment for cataracts is surgery.

How to Avoid Cataracts?

There are certain lifestyle changes and actions a person can take to potentially avoid cataracts or slow their progression. The ways to potentially avoid cataracts include wearing sunglasses, quitting smoking, having regular eye tests and managing diabetes if you have this medical condition. These suggestions on how to avoid cataracts and their definitions are listed below.

Wear sunglasses: Wearing sunglasses can help to protect the eyes from the harmful rays emitted by the sun. This can help avoid cataracts as spending prolonged periods in the sun without proper UV protection can increase a person’s risk of a cataract forming on the eye.
Quit smoking: Smoking causes many adverse effects on the whole body, including the eyes. It increases a person’s risk of developing cataracts as it can damage the proteins in the eye. Therefore, to lower the risk of a cataract forming on the eye, people should quit smoking.
Have regular eye tests: Having a regular eye test can ensure your optometrist can monitor your vision for changes and detect certain eye diseases, including cataracts. It is recommended that you have an eye test at least once every two years.
Manage diabetes: People who have diabetes have a higher risk of developing cataracts. This is due to high blood sugar leading to changes in the lens, which can speed up the formation of a cataract. Therefore, people should aim to adequately manage their diabetes.

How Can Wearing Sunglasses Help Avoid Cataracts From Developing?

Wearing sunglasses can help to prevent or slow the development of cataracts. According to the Mayo Clinic, ultraviolet light from the sun can contribute to a person’s development of cataracts. Therefore, wearing sunglasses is an important way to protect the eyes and potentially prevent cataracts from developing. For further protection, wear a wide-brimmed hat to limit the eye’s exposure to harmful UV rays emitted by the sun.

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